Nordic Naturals Vitamin D3+K2

Nordic Naturals Vitamin D3+K2 is our top pick for adults over 50 who want vitamin D and K2 together in one capsule. Vitamin D3 helps you absorb calcium and supports immune function, while vitamin K2 directs that calcium into your bones instead of your arteries. With an olive oil base for absorption and Nordic Naturals’ rigorous testing standards, this combination addresses two of the most important nutrient needs after 50 in a single daily softgel.

What Is Nordic Naturals Vitamin D3+K2?

Nordic Naturals built its reputation on omega-3 fish oils, where they’ve been an industry leader since 1995. Their expansion into complementary nutrients like vitamin D3+K2 follows the same philosophy: clean sourcing, third-party testing, and bioavailable forms that your body can actually use.

This product pairs vitamin D3 (cholecalciferol) with vitamin K2 as MK-7 (menaquinone-7) in an extra virgin olive oil base. The combination isn’t arbitrary — there’s a growing body of research showing these two fat-soluble vitamins work as a team, and taking one without the other may leave benefits on the table. Nordic Naturals was one of the first mainstream supplement brands to offer this specific pairing at a reasonable price point.

What’s Inside

Each softgel delivers 1000 IU (25 mcg) of vitamin D3 and 45 mcg of vitamin K2 as MK-7. The carrier is extra virgin olive oil, chosen because D3 and K2 are both fat-soluble vitamins that absorb significantly better with dietary fat present.

The D3 is cholecalciferol — the same form your skin makes from sunlight and the form shown in research to be 87% more potent than plant-derived D2 (ergocalciferol) at raising blood levels.

The K2 as MK-7 is the key differentiator. MK-7 has a half-life of approximately 72 hours in the body, meaning it maintains stable blood levels with once-daily dosing. The other common K2 form, MK-4, has a half-life of only 1-2 hours and typically requires multiple daily doses. For a once-a-day supplement, MK-7 is the clearly superior form.

Other ingredients are the softgel shell (gelatin, glycerin, water) and d-alpha tocopherol (natural vitamin E, used as an antioxidant to preserve freshness). No artificial colors, flavors, or preservatives.

What the Research Says

The case for combining D3 with K2 centers on calcium metabolism. Vitamin D3 increases intestinal calcium absorption — that’s well established. But more calcium in your bloodstream isn’t automatically beneficial. It needs to go to the right places (bones and teeth) and stay away from the wrong places (arterial walls).

That’s where K2 comes in. Vitamin K2 activates two critical proteins: osteocalcin (which binds calcium to bone matrix) and matrix Gla protein (which prevents calcium from depositing in arterial walls). A 2017 review in the International Journal of Endocrinology examined the evidence for D3+K2 supplementation and concluded that the combination was more effective for bone mineral density than vitamin D alone.

For cardiovascular protection, a 2015 study in Thrombosis and Haemostasis followed 244 postmenopausal women taking 180 mcg of MK-7 daily for three years. The K2 group showed significantly less arterial stiffness compared to placebo — a meaningful finding for cardiovascular health in older adults.

On the immune side, vitamin D3’s role is well-documented. The landmark 2017 BMJ meta-analysis of 25 trials showed that daily vitamin D supplementation reduced acute respiratory infections by 12% overall, with the greatest benefit (up to 70% reduction) in people who were deficient at baseline. Adults over 50 are disproportionately likely to be deficient.

Who Is This Best For?

Nordic Naturals Vitamin D3+K2 is a strong choice if you:

• Want to address immune health and bone health simultaneously — the D3+K2 combination targets both with one capsule
• Are concerned about arterial calcification — K2 actively helps keep calcium out of your arteries, which becomes increasingly relevant after 50
• Take calcium supplements — if you supplement calcium, adding K2 helps ensure that calcium goes where it should
• Want a trusted brand with clean ingredients — Nordic Naturals’ reputation for quality is well-earned
• Prefer a once-daily softgel — the MK-7 form of K2 maintains stable levels with a single daily dose

If your doctor has identified a significant vitamin D deficiency, the 1000 IU dose here may not be sufficient for repletion — you may need 2000-5000 IU initially. And if you take warfarin, K2 supplementation requires your doctor’s direct involvement.

How to Take It

Take one softgel daily with a meal that contains some fat. The olive oil base provides some fat, but taking it with a meal that includes butter, avocado, nuts, or another fat source optimizes absorption of both D3 and K2.

Timing: Morning or midday with a meal works well. Both nutrients are fat-soluble and don’t cause sleep disruption, so timing is flexible.

Critical interaction — warfarin: Vitamin K2 directly antagonizes warfarin’s mechanism of action. If you take warfarin (Coumadin), do NOT start this supplement without your doctor’s explicit guidance. Your INR levels will need monitoring. This interaction does NOT apply to newer anticoagulants like Eliquis, Xarelto, or Pradaxa, which work through a different mechanism.

Other interactions: Orlistat (Alli/Xenical) and cholestyramine can reduce absorption of fat-soluble vitamins. Space them 2 hours apart. Corticosteroids may reduce vitamin D effectiveness.

Always consult your doctor before starting D3+K2 supplementation, especially if you take blood thinners or have a history of blood clotting disorders.

The Bottom Line

Nordic Naturals Vitamin D3+K2 delivers the synergistic combination that a growing body of research supports: D3 for immune function and calcium absorption, K2 to direct that calcium where it belongs. For adults over 50 juggling bone health, immune resilience, and cardiovascular concerns, this one-capsule solution is elegant and evidence-based. The olive oil base, MK-7 form, and Nordic Naturals’ testing standards make it a supplement you can take with confidence.